575th AAA (AW) 1944-1945

I am doing research on my grandfather's unit. He was a member of the 575th Anti Aircraft Artillery during the Battle of the Bulge. He was a driver in the quad .50 cal half-tracks. I know for sure that he was involved in the liberation and followed the prisoners that were liberated from Mauthausen concentration camp. The trouble is I do not know which Company he was in. I am ultimately looking to obtain a copy yard photo from his company before they shipped. I am also looking an original DUI, but can't even find a picture of one, let alone one to buy.

His name was: Harry B. Harrison of French Lick, IN. He joined in 1943-44 and shipped form the US with the 575th AAA. All unit histories that I have found are sparse and lacking in detail. Any help with anything concerning this would be great.